The present invention relates to thread control means in a textile machine.
In German (Fed. Rep.) published patent specification No. 27 58 421 there is disclosed a weft knitting machine having at least one weft rod with a thread guide fastened thereto. The, or each such weft rod is guided at each end thereof to be displaceable in a support. A pivot arm, which is pivotably mounted on a machine frame and pivoted by a dog plate, engages the weft rod and in operation reciprocates the weft rod along its longitudinal axis. In this manner, a weft thread guided in the thread guide can be laid out transversely to the hook needles and warp threads in the machine so that it interconnects the stitches formed by the different warp threads. The supports with the weft rod or rods are, in operation, moved to and fro at right angles to the weft rod axis and approximately at right angles to the hook needles.
For the production of knit goods with fringes or laces, the weft thread guide should in addition be pivotable about the axis of the weft rod to which it is fastened. In the weft knitting machine disclosed in the above-mentioned German patent specification, there is no provision for pivotation.
In the book "Die Hakelgalonmaschine" by R. Buttner (Eugen G. Leuze Verlag, Saulgau Wurttemberg) there is described a braid-crocheting machine with a reflex turner by which it is possible to pivot a weft rod to and fro about its axis. This turner has a drive crank with a shaft parallel to the weft rod. The drive crank is connected by a rod with a crank which is mounted in a support serving for guidance of the weft rod. The movement of the crank is transmitted through a ratchet wheel to a cylinder, which is provided with detachable dogs arranged in accordance with the pattern to be produced. The dogs are scanned by a feeler lever which is mounted in the support to be pivotable about a pivot axis extending parallel to the weft rod. The feeler lever, together with an additional lever, retains the rod to which the thread guide is fastened.
This turner does, however, have a number of disadvantages. Due to its complicated construction, it only allows low operating speeds. Moreover, only relatively simple patterns can be produced, because the dog cylinder, which is moved along with the support, cannot be made as large as desired. It is also not possible to control the pivotal motion of the thread guide by the same dog cylinder, or by dog chains of like kind used for controlling the reciprocating displacement of the weft rod or rods.
There is also described in "Die Hakelgelonmaschine" a machine in which a bracket forming a cam is fastened to a longitudinally displaceable weft rod. An arm is fastened to an axially non-displaceable rod to be pivoted, which extends transversely to this rod and is provided with a feeler roller. The roller follows the cam and is held thereagainst by a spring acting on the arm. The weft rod provided with the bracket can be displaced in its longitudinal direction by a Jacquard pull. This displacement then effects, through the bracket and the arm, a pivotation of the rod to be pivoted.
The machine has the disadvantage that the pivotable rod can be pivoted but not axially displaced. Furthermore, one of the weft rods, namely the weft rod provided with the bracket, is used exclusively for converting a linear displacement motion into a pivotal motion. Since braid-crocheting machines for reason of space, among other reasons, can usually only be equipped with a relatively small number of weft rods, for example about six weft rods, the possibilities for formation of patterns are greatly restricted when one of the weft rods is exclusively pivotable and another of the weft rods has to be used to generate this pivotation. Moreover, it is not possible with the previously known reflex turner to vary the magnitude of the pivotation according to a predetermined program, which further restricts the scope for formation of patterns. Furthermore, the known turner only permits relatively low operating speeds.
A device for the pivotation of the thread guide rod of a braid-crocheting machine is also disclosed in German (Fed. Rep.) patent specification No. 542 184. The thread guide rod is pivotably mounted in bearings. A slide is guided at one end of the thread guide rod to be displaceable therealong. The thread guide rod is secured against axial displacement by two setting rings firmly clamped thereto. One of these setting rings is provided with a pin which projects into a bevelled slot of a strap fastened to the slide. The slide and the strap can be displaced by Jacquard chain pins. Because the slot in the strap is bevelled, the pin is laterally deflected on displacement of the slide and strap. The pin and the setting ring, to which the pin is fastened, thus together from a crank which converts the axial reciprocating movement of the slide and strap into pivotal movement of the thread guide rod. The strap is additionally secured to the slide to be radially adjustable with respect to the axis of the thread guide rod.
On displacement of the slide, the pin is not only deflected laterally, but also changes its angle of inclination with respect to the strap. The pin must therefore be guided in the strap with a relatively large amount of play. This is particularly so because the strap is after all, radially displaceable relative to the thread guide rod. Furthermore, the pin in at least part of its range of settings bears against the strap at only one point. This has the disadvantage that operation is possible only with relatively low frequencies of pivotation and that wear is relatively high. Moreover, the angle of pivotation must be kept relatively small, otherwise the above-mentioned play must be increased, and the thread guide rod is not axially displaceable.
The present invention therefore has the task of providing a thread control means in which a thread guide means, including a thread-deflecting means, can be pivotable around a pivot axis at a high cyclic frequency even with complicated pattern programs. Furthermore, it should be possible, if required, to additionally displace the thread guide to and fro along the pivot axis and independently of the pivotation.